Presser foot for sewing machines



July 4, 1967 H. CIECIOR 3,329,115

PRESSER FOOT FOR SEWING MACHINES Filed April 29, 1965 5 Sheets-Sheet l July 4, 1967 H. CIECIOR PRESSER FOOT FOR SEWING MACHINES 5 Sheets-$heet 2 Filed April 29, 1965 July 4, 1967 CIECIOR 3,329,115

PRESSER FOOT FOR SEWING MACHINES Filed April 29, 1965 5 Sheets-Sheet 5 United States Patent 3,329,115 PRESSER FOOT FOR SEWING MACHINES Heinrich Ciecior, Ettlingen, Baden, Germany, assignor to Industrie-Werke Karlsruhe Aktiengesellschaft, Karisruhe, Germany Filed Apr. 29, 1965, Ser. No. 451,880

Claims priority, application Germany, July 24, 1964,

3 Claims. (Cl. 112-235) ABSTRACT OF THE DISCLOSURE A presser f-oot mechanism for a sewing machine in which for the purpose of sewing thin and delicate fabrics the pressure of the presser foot is compensated by an adjustable counter spring mechanism which is adapted to be adjusted so accurately that only a skid spring on the presser foot becomes active during the sewing operation.

The invention relates to sewing machines and particularly to an improved presser foot mechanism.

It is an object of the invention to provide a presser foot mechanism particularly for rapidly operating sewing machines in which thin and delicate fabrics are engaged by the presser foot with spring pressure.

Another object of the invention is to provide a presser foot mechanism in which the pressure of the presser foot during the advance of the fabric is reduced to the absolute smallest one.

In accordance with the invention, the pressure of the conventional pressure foot spring and the weight of the presser foot linkage is compensated by an adjustable counter spring mechanism so that only the pressure of a skid spring attached to the presser foot becomes active.

The counter spring is adapted to be adjusted so accurately that only the skid spring is raised by the fabric advancing member during the advance of the fabric, which means that presser foot per se and its presser rod perform substantially no movement during the sewing of the fabric which assures a soft advance of the fabric.

These and other objects of the invention are described in detail in the following description having reference to the accompanying drawings, in which:

FIG. 1 is a side elevation view, with parts in section, of that portion of a sewing machine equipped with the presser foot mechanism of the invention;

FIG. 2 is a view at right angles to FIG. 1 and shows a side view of the sewing arm and parts in section to disclose other details of the sewing machine provided with the invention; and

FIG. 3 is a horizontal sectional view along the line IIIIII of FIG. 1.

Referring to the drawings, see FIG. 1, the sewing machine arm 1 has vertically slidably mounted in the same a vertical presser foot rod 2 at the lower end of which is attached a presser foot 15. Two superimposed and rather heavy leaf springs 3 and 3a are horizontally mounted on top of the arm 1, as particularly shown in FIG. 2.

The lower longer leaf spring 3 engages with one of its ends a ball 5 arranged in a suitable spherical seat 50 provided in the upper end face of the rod 2. A vertical threaded rod 4a fixed to the arm 1 extends with clearance through suitable apertures in the center portions of the leaf springs 3 and 3a, and a knurled adjustable nut 4 at the upper end of the rod 4a engages the upper leaf spring 3a and is adapted to change the pressure of the springs 3 and 3a which is effective on the upper end of the presser rod 2.

A guide rod 6 is arranged in parallel spaced relation to the presser rod 2 and carries at its lower portion a helical counter spring 7. The lower end of the spring 7 engages a setting collar 8 fixedly attached to the lower end of the guide rod 6. The upper end of the spring 7 engages a short flanged sleeve 9 slidably mounted on the guide rod 6 and engaging the lower face of a forked connecting arm 10 which is attached by two screws 10a to the presser rod 2. The upper portion of the guide rod 6 extends slidably through a guide sleeve 11 fixedly attached to the sewing machine arm 1. The upper end 6a of the guide rod 6 is threaded and in threaded engagement with a bar 12 fixedly attached by two screws 13 to the arm 1. At the extreme upper end, the guide rod 6 has fixed thereto a knurled button 14 for rotatably adjusting the guide rod 6 in axial direction either upwardly or downwardly. Such an axial adjustment of the guide rod 6 causes the helical spring 7 to counteract more or less the pressure of the leaf springs 3 and St: on the upper end of the presser rod 2. The forked end 10b of the connecting arm 10 slidably engages the lower end of the guide sleeve 11, as shown particularly in FIG. 3, and prevents a rotative movement of the presser rod 2. The axial adjustment of the guide rod 6 is made in such a manner that the pressure of the leaf springs 3, 3a including the weight of the presser rod 2, and the presser foot 15 is completely compensated by the counter pressure of the helical spring 7. Thereupon, the guide rod 6 is locked in this adjusted position by a knurled locking nut 16 which is threaded on the upper threaded portion 6a of the guide rod 6.

The presser foot 15 has mounted thereon a skid spring 17 made of a strip of resilient sheet material. This skid spring 17 is slightly spaced below the flat lower face of the presser foot 15 and engages with a U-shaped flange 25 at one end an undercut shoulder 15a on the presser foot 15. The other end 26 of the skid spring 17 is bent rearwardly to form an acute angle with the body of the skid spring 17 and is attached by screws 18 to an inclined projection 15b on the pressure foot 15.

The presser foot is adjusted to such a height that when the fabric advancing member 27 is in its lower position, the fabric to be sewn is pressed with the required spring pressure against the sewing or stitching plate 28 and the spring movement of the skid spring 17 at the upper position of the fabric advancing member 27 may still be fully utilized.

The raising of the presser foot 15 for inserting the fabric or for moving the fabric is accomplished by a bell crank lever 20, see FIG. 2 which, in well known manner, is actuated by a knee or foot operated linkage 21, 22, 23 and 24. This bell crank lever 20 is arranged to engage the lower face of the connecting arm 10 for raising it and therewith the rod 2 is raised against the force of the leaf springs 3 and 3a.

What I claim is:

1. In a sewing machine, a presser foot mechanism comprising an axially slidably mounted presser rod, a presser foot at one end thereof, spring means for urging said presser rod in one direction, counter spring means for urging said presser rod in the other direction, said counter spring means including, a guide pin arranged parallel to said presser rod, a helical spring on said guide pin, a collar fixed to said guide pin, an arm fixed to said presser rod and embracing said guide pin, said helical spring being disposed between said collar and said arm for urging the same in a direction opposed to the direction in which said arm is urged by said presser rod and said spring means, means for axially adjusting said guide pin for adjusting said counter spring means to such a position that it compensates the pressure of said spring means and the weight of said presser rod and said presser foot, and

a skid spring on said presser foot the pressure of which is the only one acting on the fabric being sewed.

2. In a sewing machine, a presser foot mechanism comprising an axially slidably mounted presser rod, a presser foot at one end thereof, spring means for urging said presser rod in one direction, counter spring means for urging said presser rod in the other direction, said counter spring means including a guide pin arranged parallel to said presser rod, a helical spring on said guide pin, a

collar fixed to said guide pin, an arm fixed to said presser rod and embracing said guide pin, said helical spring being disposed between said collar and said arm for urging the same in a direction opposed to the direction in which said arm is urged by said presser rod and said spring means, means for axially adjusting said guide pin for adjusting said counter spring means to such a position that it compensates the pressure of said spring means and the weight of said presser rod and said presser foot, means for locking said guide pin in said adjusted position, and a skid spring on said presser foot the pressure of which is the only one acting on the fabric being sewed.

3. In a sewing machine, a presser foot mechanism comprising an axially slidably mounted presser rod, a presser foot at one end thereof, spring means for urging said presser rod in one direction, counter spring means for urging said presser rod in the other direction, said counter spring means including a guide pin arranged parallel to said presser rod, a helical spring on said guide pin, a collar fixed to said guide pin, an arm fixed to said presser rod and embracing said guide pin, said helical spring being disposed between said collar and said arm for urging the same in a direction opposed to the direction in which said arm is urged by said presser rod and said spring means, means for axially adjusting said guide pin for adjusting said counter spring means to such a position that it compensates the pressure of said spring means and the weight of said presser rod and said presser foot, and a skid spring on said presser foot the pressure of which is the only one acting on the fabric being sewed, said skid spring comprising a strip of resilient sheet material attached with its ends to the respective ends of said presser foot, with the entire lower face of said presser foot in slightly spaced parallel relation from the major length of said strip of resilient sheet material.

References Cited UNITED STATES PATENTS 1,350,301 8/1920 Voe 112-225 1,820,460 8/1931 Jones l12235 1,880,749 10/1932 Bowman 112-235 1,952,535 3/1934 Christensen et al. 112235 PATRICK D. LAWSON, Primary Examiner. 

1. IN A SEWING MACHINE, A PRESSER FOOT MECHANISM COMPRISING AN AXIALLY SLIDABLY MOUNTED PRESSER ROD, A PRESSER FOOT AT ONE END THEREOF, SPRING MEANS FOR URGING SAID PRESSER ROD IN ON ONE DIRECTION, COUNTER SPRING MEANS FOR URGING SAID PRESSER ROD IN HE OTHER DIRECTION, SAID COUNTER SPRING MEANS INCLUDING, A GUIDE PIN ARRANGED PARALLEL TO SAID PRESSER ROD, A HELICAL SPRING ON SAID GUIDE PIN, A COLLAR FIXED TO SAID GUIDE PIN, AND ARM FIXED TO SAID PRESSER ROD AND EMBRACING SAID GUIDE PIN, SAID HELICAL SPRING BEING DISPOSED BETWEEN SAID COLLAR AND SAID ARM FOR URGING THE SAME IN A DIRECTION OPPOSED TO THE DIRECTION IN WHICH SAID ARM IS URGED BY SAID PRESSER ROD AND SAID SPRING MEANS, MEANS FOR AXIALLY ADJUSTING SAID GUIDE PIN FOR ADJUSTING SAID COUNTER SPRING MEANS TO SUCH A POSITION THAT IT COMPENSATES THE PRESSURE OF SAID SPRING MEANS AND THE WEIGHT OF SAID PRESSER ROD AND SAID PRESSER FOOT, AND A SKID SPRING ON SAID PRESSER FOOT THE PRESSURE OF WHICH IS THE ONLY ONE ACTING ON THE FABRIC BEING SEWED. 